1. Strength Training without Weights
Hoger, Sharon A. , Hoeger, Werner W.K. Principles and Labs for Fitness and Wellness

2. Chair Squats
Action: Place a chair just behind you and stand in front of it with feet about hip- or shoulder-width apart. Contract the abs and keep them tight as you bend the knees and slowly squat towards the chair. Keep the knees behind the toes as you sit down on the chair for a few seconds. Contract the glutes and hamstrings to lift up out of the chair and begin extending the legs. Fully extend the legs until you're back to standing position. To progress, squat down until you're just hovering over the chair, but not sitting all the way down. Always keep the knees in line with the toes.
Muscles Developed:
hips, gluteal muscles and quadriceps.

3. Modified Dips
Action: Using a gymnasium bleacher, box, chair with arms, dip down at least 90 degrees angle at the elbow joint and then return to the initial position.
Muscle Developed: Triceps, Deltoids, and pectoralis major

4. Rowing Torso
Action: Raise your arms laterally (abduction) to a horizontal position and bend your elbows to 90 degrees. Have the partner apply enough pressure on your elbows to gradually force your arms forward while you try to resist the pressure. Next, reverse the action, horizontally forcing the arms backward as your partner applies sufficient forward pressure to create resistance.
Muscles Developed: deltoids, rhomboids, trapezius

5. Heel Raises
Action: From the standing position with feet flat on the floor or at the edge of a step raise and lower your body weight by moving at the ankle joint only. For added resistance have someone else hold your shoulders down as you perform the exercise.
Muscles Developed: Gastrocnemius and Soleus

6. Leg Abduction/Leg Adduction
Action: Both participants sit of the floor. The person on the left places the feet on the inside of the other person’s feet. Simultaneously, the person on the left presses the legs laterally (to the outside –abduction) while the period on the right presses the legs medially (adduction) Hold the contraction for 10 seconds. Repeat the exercise at all three angles, and then reverse the pressing sequence.
Muscles Developed: Hip abductors and adductors

7. Push Up
Action: Maintaining your body as straight as possible (a) flex the elbows, lowering the body until you almost touch the floor (b) then raise yourself back up to the starting position. If you are unable to perform the push-up as indicated, decrease the resistance by supporting the lower body with the knees rather than the feet (c)
Muscles Developed: Triceps, deltoid, pectoralis major, abdominals, and erector spinae.

8. Bicep Curl / Tricep Pushdown
Action: Partner and lifter stand facing each other about 12" apart. Lifter grabs center of towel with both hands, palms up. Partner grabs either end of the towel, also with palms up (hands are about 6-12" away from one another).
 Lifter curls the towel up (biceps curl) as partner resists. Lifter then presses the towel town (triceps pushdown) as the partner resists. Partner and lifter should then reverse hand positions and switch repeat exercise.
Muscles Developed: Bicep, Brachloaradialis, brachialis, Triceps,

9. Assisted Row
This exercise requires a towel (larger shower towels work best). Lifter and partner sit across from each other as if they were using the cable row machine at the gym (legs straight out in front of them, with soles of shoes touching).
Action: The lifter should grab the towel with an underhand grip, while the partner grabs the towel at either end (hint, the closer the lifter's and partner's hands are placed on the towel, the harder the exercise will be to perform).
Muscles Developed: Posterior Deltoid, rhomboids, trapezius

10. Seated Military Press
Action: Lifter can sit on a stability ball, bench, chair or whatever is available as long as there is room behind them for the partner to stand.
Lifter starts by putting arms in a military press position (upper arms parallel with the ground and arms bent 90 degrees at the elbow). Partner places hands on top of lifter's hands and partner provides enough resistance that allows the lifter to complete each concentric part of the repetition in approximately 3 seconds.
Muscles Developed: Triceps, deltoid, pectoralis major

11. Leg Extension
Action: Lifter sits in a chair or on end of table so feet are not able to touch the ground. Partner grabs ankles (where the pad of a leg extension machine would be).
As lifter performs a leg extension, partner resists the lifting portion of the movement. The partner should then put resistance on the ankles as lifter lowers legs forcing lifter to resist during the lowering of the movement.
Muscle Developed:
Quadriceps

12. Leg Curl
Action: Lifter lays flat on the bench facing down. Partner grabs back of ankle. As the lifter performs the leg curl, partner resists the lifting portion of the movement. The partner should then put resistance on
the ankles as the lifter pulls legs toward the butt.
Muscles Developed: Hamstrings

13. Leg Curl / Leg Extension
Action: Lie on the floor face down. Cross the right ankle over the left heel (a) Apply resistance with your right foot while you bring the left foot up to 90 degrees at the knee joint (b) Apply enough resistance so the left foot can only be brought up slowly. Repeat the exercise, crossing the left ankle over the right heel.
Muscles Developed: Hamstrings and Quadriceps

14. Lunges
Action: Keep your upper body straight, with your shoulders back and relaxed and chin up (pick a point to stare at in front of you so you don't keep looking down). Always engage your core. Step forward with one leg, lowering your hips until both knees are bent at about a 90-degree angle. Make sure your front knee is directly above your ankle, not pushed out too far, and make sure your other knee doesn't touch the floor. Keep the weight in your heels as you push back up to the staring position.
Muscles Developed: hamstrings, gluteal muscles and quadriceps

15. Lateral Bridges

16. Prone Bridge

17. Step Ups
Action: Step up and down using a box or chair approximately 12 to 15 inches high (a) Conduct on set using the same leg each time you step up, and then conduct a second set using the other leg. You also could alternate legs on each step-up cycle. You may increase the resistance by holding an object in your arms. (b) Hold the object close to avoid strain on the lower back.
Muscle Developed: Gluteal muscles, quadriceps, gastrocnemius, and soleus.

18. Wall Sit
Action: Stand in front of a wall (about 2 feet in front of it) and lean against it. Slide down until your knees are at about 90-degree angles and hold, keeping the abs contracted, for seconds. Come back to start and repeat, holding the squat at different angles to work the lower body in different ways. To add intensity, hold weights or squeeze a ball between the knees.
Muscles Developed: gluteal muscles and quadriceps.

19. Reverse Crunches